This part of ISO 6358 specifies a steady-state method for testing pneumatic fluid power components that use compressible fluids, i.e. gases, and that have internal flow paths that can be either fixed or variable in size, to determine their flow-rate characteristics. However, this part of ISO 6358 does not apply to components whose flow coefficient is unstable during use, i.e. components that exhibit remarkable hysteretic behaviour (because they can contain flexible parts that deform under the flow) or that have an internal feedback phenomenon (such as regulators). In addition, it does not apply to components that exchange energy with the fluid during flow-rate measurement, e.g. cylinders, accumulators, etc. Table 1 provides a summary of which parts of ISO 6358 can be applied to various components. This part of ISO 6358 specifies requirements for the test installation, the test procedure, and the presentation of results for the steady-state method. This part of ISO 6358 includes several test procedures, including the one described in Annex A, which is from ISO 6358:1989. Flowmeter calibration is described in Annex B. Evaluation of measurement uncertainties is described in Annex C. Observations of the error in the test results are described in Annex D. Equations and graphical representations of flow-rate characteristics are given in Annex E. Guidance on the use of practical units for the presentation of results is given in Annex F. Test results using commercially available pneumatic components are given in Annex G. Guidance on calculating the flow-rate characteristics is given in Annex H.